Decoding does not detect overflowing correctly and returns a number

[oblique]

Decoding does not detect overflowing correctly and returns a number. This can accept malformed data and cause misbehaviours.

Reproduction:

fn main() {
    let number = u64::MAX as u128 + 10000;

    let mut buf = unsigned_varint::encode::u128_buffer();
    let bytes = unsigned_varint::encode::u128(number, &mut buf);

    println!("input number: {number}");
    println!("input bytes: {bytes:02x?}");

    let (output, _rest) = unsigned_varint::decode::u64(&bytes).unwrap();
    println!("output number: {output:?}");
}

input number: 18446744073709561615
input bytes: [8f, ce, 80, 80, 80, 80, 80, 80, 80, 02]
output number: 9999

[stringhandler]

Possibly fixed in #68 ?